#-*-coding:UTF-8 -*-
#显示公约数
'''
Created on 2013-6-5

@author: hanjiewu
'''
def showMaxFactor(num):
    count = num / 2
    while count > 1:
        if num % count == 0:
            print 'larget factor of %d is %d' % \
            (num, count)
            break
        count -= 1
    else:
        print num, "is prime"

if __name__ == "__main__":
    for eachNum in range(10, 21):
        showMaxFactor(eachNum)
